Category How to Find the Apollo Landing Sites

From the standpoint of the Apollo program, NASA planners desired an initial target area to be one of typical mare and near the lunar equator. The selected region was a relatively detached sea between Ocean of Storms and Sea of Clouds, bounded by the Riphean Mountains on one side and the bright cratered area containing Guericke Crater and Parry-Bonpland Crater on the other.

The mission objective of Ranger 7 was carried out flawlessly by obtaining close – up pictures of the lunar surface for the benefit of both the scientific community and the Apollo program planning. Ranger 7 transmitted approximately 4,000 television pictures of the target area before smashing itself in the lunar surface. The signals from the six television cameras aboard the spacecraft were transmitted during the last 17 minutes of the flight. The picture taking spanned a distance range from slightly more than 1,800 miles to approximately 500 yards above the surface.

The basic objective in selecting the Ranger 8 impact site was to choose an area which, in conjunction with the Ranger 7 photographs, would provide a more com­plete knowledge of the lunar maria within the Moon’s equatorial zone. Applying the newly evolving Apollo constraints, a point near the equator and 15° from the termi­nator was chosen.

The Moon has long held the fascination of mankind. It is the biggest and the brightest object in the night sky. Man has gazed upon the Moon for centuries with awe and imagined journeys there. Great, and not-so-great, literature has been written over the centuries, both prose and poetry, about the Moon. Nature itself has adapted to and has synchronized to the rhythms and timing of the lunar cycle in determining reproduction, migrations, and other organic activities. The contribution of the Moon to life on Earth, and to mankind and his culture is extensive.

Before proceeding to the pictorial portion of this book, there are some basics about the Moon that will help with observing it and appreciating the photos herein.

The Moon is the largest natural moon in proportion to its primary planet in the solar system. It orbits the Earth in an elliptical orbit, with a perigee of 225,741 miles and an apogee of 251,968 miles at an orbital inclination to the ecliptic of 5.125°. This inclination translates to between 18.29° to 28.58° to the Earth’s equa­tor. The Moon has a mean radius of 1,737.1 miles, is spherical in shape, although it is slightly flattened due the gravitational force of the Earth. The lunar mass is

0. 0123 that of Earth. Gravity on the Moon is 0.165.4 g. To launch back into lunar orbit, Apollo Lunar Module (LM) astronauts needed only an escape velocity of 2.38 km/s, as compared to the escape velocity of Earth of 11.2 km/s.

The Moon is the second brightest celestial object that can be seen from Earth, with only the Sun outshining it. At full phase, the Moon shines at -12.74 magni­tude. Unlike the Sun, where direct viewing can cause permanent eye damage with­out proper equipment and eye protection, the Moon can be readily observed safely. The Moon has an albedo of 0.136, which is the ratio of reflected sunlight to the sunlight that hits it. Moonlight does not possess the heat that is characteristic of direct sunlight, and thus cannot cause eye damage. A full Moon can be uncomfortably bright, but it is safe to view. The angular diameter of the Moon for Earth bound observers varies from 29.3 to 34.1 arc minutes.

Commonly thought of as being airless, the Moon possesses a very, very slight atmosphere. Atmospheric pressure varies from a daylight level of 0.0000001 to 0.0000000001 pascals This thin lunar atmosphere consists of argon, helium, hydro­gen, potassium, and radon gases.

The Moon is in synchronous rotation with the Earth, thus always showing the same face towards Earth. Because of the Moon’s orbital inclination and it’s ellipti­cal orbit, roughly 64 % of its near face can be seen and mapped from Earth, but not all at one time.

Throughout the history of manned spaceflight, both astronauts and cosmonauts have experienced both short term and long term effects from their time away from Earth’s gravity. In the relatively short period the Apollo astronauts traveled to the Moon and back, mostly short term effects were experienced, but the longer periods spent on the ISS have shown some long term effects that can be detrimental to Mars-bound space explorers.

The human cardiovascular system circulates fluids through the body, pushing against gravity to prevent blood from pooling in the legs and bringing blood to the brain. In the microgravity of space, the cardiovascular system is not taxed as hard, triggering a fluid shift. As fluids move up from the lower body to the trunk, the heart rate increases and blood pressure rises. Astronauts experience puffy faces, headaches, nasal congestion and skinny “bird” legs as a result. Additionally, over a third of all astronauts experience some form of motion sickness in space because of the blood circulation changes. Symptoms of space sickness, including nausea and vomiting, headaches, malaise and dizziness, usually subside within 2 or 3 days.

Some evidence suggests that microgravity causes astronauts’ red blood cells to change. The red blood cells appear to change shape in space, becoming more spherical, and fewer cells populate bone marrow. Cells do return to normal once back under Earth-normal gravity however, even after a long-term mission.

Astronauts returning from missions have been found to be more prone to infec­tion, both viral as well as bacterial and fungal. Long term studies in space and Antarctica have shown that isolation and sleep deprivation may result in a weakened T-lymphocyte system, leading to compromised immunity. A high probability of increased allergy symptoms has been noted. The immune system is unable to adapt under microgravity conditions. A future Mars-bound crew will need a supply of antibacterial, anti-fungal, and antiviral drugs and medications. A Mars mission that extends beyond 6 months will mean these drugs will reach their expiration dates, thus inviting the need for some pharmaceutical capability onboard. A shorter 39-day-to-Mars mission reduces this risk.

A well known effect of microgravity is the atrophy the muscular structure. Astronauts onboard the ISS counter these effects by exercising up to 2 hours a day.

The microgravity of space triggers the human body to excrete calcium and phos­phorus (in urine and feces), resulting in rapid bone loss. On the shorter duration Apollo missions, the calcium and phosphorus loss was minimal, and the Apollo astronauts quickly recovered their bones density. A 2 year or longer Mars mission can result in an astronaut’s bone density loss to be equivalent to a lifetime on Earth. Like osteoporosis on Earth, bone loss in space can lead to fractures, weakness and painful urinary stones. The most dramatic changes occur in the heel bone, femoral neck, lumbar spine and pelvis. Exercise in space and upon return can help slow the loss, but it will take 2 years or more of dedicated, consistent training upon return to repair it. Artificial gravity would also serve to mitigate this problem if it is a part of the mission design.

All Apollo missions conducted the Light Flashes Experiment in an effort to explain the flashes of light that seem to appear behind the astronaut’s eyelids. The result of the experiment showed that galactic cosmic rays passed through the astro­naut’s brains causing the retinal flashes. These flashes are just symptomatic of a much larger problem. Cosmic rays and the radiation effects of solar flares expose astronauts to high levels of ionizing radiation. The Apollo astronauts were fortunate that during their missions, other than the light show they experienced when they closed their eyes, no solar flares occurred. A solar flare had the potential of causing the loss of the LM crew on the lunar surface. The LM construction and the lunar spacesuits provided minimal radiation shielding.

Unrelated to the light flashes, medical doctors and scientists are showing some concern over a possible loss of eyesight from extended microgravity exposure. NASA has reported that 15 male astronauts returning from extended missions in space have experienced confirmed visual and anatomical changes during or after long-duration flights. It is continuing to be studied, with current thought being related to ocular fluid shifts due to microgravity as a contributing factor.

The radiation in deep space can damage atoms in human cells, leading to decreased immunity and a higher risk of cataracts, cancer, heart disease, damage to the central nervous system and brain damage. Recognize that Mars does not have a global magnetic field to shield the planet from solar radiation particles, nor does it have a thick atmosphere to help filter out cosmic rays. Long-term exposure to ion­izing radiation in open space and on the planet surface is a significant concern for the crew of the Mars mission.

The Radiation Assessment Detector (RAD) aboard the Mars rover Curiosity produced detailed measurements of the absorbed dose, and dose equivalent from galactic cosmic rays, and solar energetic particles en route and from the surface of Mars. The numbers from the RAD are startling high. For the round trip, based on Curiosity’s RAD data, an astronaut would receive radiation from both cosmic gamma rays and solar activity approximately 0.66 Sv during a 180 day flight to Mars.

A 500 day exposure on the surface of Mars would result in each astronaut receiv­ing approximately 1 Sv. Long-term population studies have shown that exposure to radiation increases a person’s lifetime cancer risk; exposure to a dose of 1 Sv is associated with a 5 % increase in fatal cancer risk. NASA has established a 3 % increased risk of fatal cancer as an acceptable career limit for astronauts in low earth orbit, such as extended stays on the ISS. NASA has not established a limit for deep space missions.

A number of solutions are being explored to help protect astronauts, including antioxidant-rich foods, such as blueberries and strawberries and close monitoring of radiation levels combined with the use of radiation shields. Protection from solar flares, however, poses a technological problem that is solvable at the price of addi­tional weight of protective shielding.

Astronauts returning to Earth risk low blood pressure. A sudden reintroduction of gravity makes the blood in astronauts’ bodies rush down, resulting in dizziness and lightheadedness. Tiny muscles in veins that send blood uphill can atrophy after prolonged periods of microgravity, and can fail to push blood back up to the heart. Astronauts can experience fainting or be unable to remain standing. Mir cosmo­nauts had to be carried off their landing craft by stretcher due to the severe drop their blood pressure following long missions. A prolonged mission to Mars will result in returning astronauts needing to drink salt water to increase the volume of fluids in their bodies, wear G-suits (rubberized full body suits which are inflated to squeeze the extremities) or potentially use new drugs to increase blood pressure.

Apollo moon missions took several days to transition from Earth orbit to the Moon, with the Earth within of a few days reach and communications links with only a handful of seconds latency. The manned mission to Mars will not have those luxuries. The travel time to and from Mars will be measured in terms of months or years, not days. Communication latency will be measured in terms of a maximum of 22 minutes, not seconds.

Medical aid for Space Shuttle missions and ISS missions can be accommodated with near real-time communications, on board supplies, and in an emergency, a relatively timely re-entry and return to Earth. A Mars mission, as it progresses towards its goal, will not have the luxury of a quick and timely return to Earth in case of medical emergency. Any real-time communications to guide the crew through a medical procedure will be severely handicapped by the communications delay because of the distance.

A different medical philosophy is required, utilizing lessons learned from the Apollo, Space Shuttle, long-term Antarctic, and ISS experiences. Five decades of American and Russian spaceflight have yielded a greater understanding of space medicine and the effects of weightlessness on the human body. The development of a comprehensive Mars healthcare system will allow for autonomous health care, with a combination of advanced medical instrumentation, medical training of the crew, and the possible selection of a medical doctor for inclusion as part of the Mars crew. It will need to support the Mars crew members for both the journey to and from Mars, and surface activities. The medical system must accommodate a wide array of human illness and conditions, while being prepared for emergencies caused by accidents. In addition, the medical system will incorporate both environ­mental monitoring and exercise countermeasures to ensure wellness and maintain crew health.

The return to Earth from Mars will likely require a quarantine period for the same reasons the crews of Apollo 11, 12, and 14 experienced. It is unknown if there is any microbial life on Mars, harmful or otherwise. A quarantine in an environment external to Earth would be prudent to avoid any possible contamination of Earth. A likely site might be at or near an established Moon base. Isolation could be conducted on an Earth-orbital quarantine module, perhaps in conjunction and monitored by personnel with the ISS.

The majority of telescope owners make their observations through an eyepiece using one eye. The human brain is designed to process visual images through two eyes. There are two options for viewing the Moon, the planets and stars with two eyes. One is REALLY expensive – binocular telescopes. The other option is rela­tively affordable – the binoviewer. The binoviewer uses a system of prisms to split the single light path of a telescope into two separate light paths to two eyepieces. This beam-splitting fools the eyes and the brain into thinking it is seeing an object in stereo. The results are spectacular when viewing the Moon. At certain high mag­nifications, and by allowing the Moon to drift through the field-of-view, the observer gets the sensation of orbiting the Moon and seeing the view that the Apollo command module pilot would see in orbit. With both eyes open, the lunar landscape seems to glide smoothly past. Even when tracking, the lunar landscape seems to take on three dimensions. The downside to owning a binoviewer is threefold:

• There is a slight light loss using a binoviewer because of the additional light splitting optics. But for a bright object like the Moon, this is not a problem. For planetary views, the light loss is not of great impact. Deep sky observing can be problematic, especially with dim objects.

• There is the additional expense of the binoviewer and buying two of every eye­piece. And you are limited to 1.25 in. sized eyepieces.

• Many telescopes do not have enough in-focus to accommodate a binoviewer. SCTs and Maks focus by moving the primary mirror and binoviewers work well with these types. Some refractors are manufactured with shorter tubes to accom­modate the binoviewer, and provide extension tubes to use for mono viewing. Many binoviewers have an optional Barlow-like attachment to allow focusing with other types of telescopes, which limits the low power magnification range.

The prime objective of the mission, to obtain high-resolution photographs of Sea of Tranquility, was met. During the 23 minutes the cameras operated before impact, a large swath of the Moon was photographed at high resolution for the first time. Excellent photographs of Delambre Crater, the southern shoreline of Sea of Tranquility, and the crater pair Ritter and Sabine were obtained. The last picture was taken 0.09 second before impact from an altitude of approximately 500 feet. The impact point was less than 12 miles from the selected target. The eventual Apollo 11 landing site can be found among the Ranger 8 photograph series.

Since Ranger 7 and 8 missions had successfully provided high-resolution coverage to the two principal types of mare, it was decided that Ranger 9 photograph other types of terrain. Mission planners eventually settled on the highlands surrounding the Alphonsus Crater as the target.

The Ranger 9 flight concluded the Ranger series in a spectacular fashion, with the direct broadcast of the B-camera telecast over national television as the space­craft approached the Moon. Unlike its predecessors, which photographed relatively simple mare terrain, Ranger 9 was directed to one of the more highly featured areas of the Moon. The impact point was selected slightly northeast of the central peak of Alphonsus Crater. The last picture was taken 0.25 second before impact from an altitude of approximately 2,000 feet. The terminal resolution of approximately 1 feet bettered that of both Ranger 7 and 8.

Waxing, waning, first quarter, gibbous Moon, half Moon, full Moon, third quarter, waning Moon – the vocabulary for the different phases of the Moon can be and is daunting and confusing. Since sighting and observing the Apollo landing sites is dependent on the phase of the Moon for best views, it is best to review and clarify the various terms.

1. The Crescent Moon can be seen in the first 5 days after the New Moon. The line that differentiates the sunlit Moon and the dark shadowed Moon is known as the terminator (the reader can insert their own sci fi movie joke here). The crescent moon also represents the waxing phase of the Moon, with waxing describing the gradual illumination towards the full Moon. During the waxing phase of the Moon, the terminator begins on the eastern edge of the Moon and on subsequent days proceeds westward. The crescent Moon is a very attractive phase of the Moon, with deep shadows from the mountains and within craters. Look for the peaks of lunar mountains being illuminated while the lower elevations are still enshrouded in darkness. However, this early phase is of little interest to the observer seeking to discover the Apollo landing sites, since none are illuminated by sunlight at this time.

2. The next 3 days, days 6, 7, and 8, are the half Moon phase. This term is clearly named as half of the Moon being illuminated by sunlight. Confusingly, this phase can also be referred to as the first quarter. The lunar cycle proceeds from new Moon, first quarter, full Moon, last Quarter, and back to new Moon. The Moon is still waxing towards full. This is when the first opportunity is provided to view the Apollo landing sites. The earliest Apollo site to be clearly visible is the Apollo 17 on day 6, although sometimes Day 5 provides a glimpse. By Day 8, all Apollo landing sites with the exception of Apollo 12 can be seen during this half Moon phase.

3. Days 9 through 11 represents the gibbous Moon, which for all intents and pur­poses means more than half but less than full. The Moon is still waxing towards a full Moon. By now all the Apollo sites are visible to the earthbound observer. For amateur astronomers, the lead up to the full Moon is the best observing period since the terminator (the line separating sunlight lit and dark) provides shadows that can provide a 3D effect in lunar observations.

4. The Full Moon on days 12-16 are obviously days for locating the Apollo sites, although the full Moon can appear very bright. The brightness of the Moon will not damage the viewer’s eyesight (never look at the Sun unless properly equipped.), although some personal comfort benefits can be gained from using neutral density filters or polarizing filters to calm down the brightness of the moonlight. Because of the lack of shadows, the Moon tends to look a little flat from the direct reflection of sunlight and the lack of shadows.

5. The last 2 weeks of the lunar phases represent the Waning Moon, as the Moon passes through from Full, to waning gibbous, to half or Last Quarter Moon, to waning crescent. After the Full Moon, the terminator moves towards the western limb of the Moon. Like the waxing Moon, the waning Moon can afford very pleasing views cause of increasing amounts of dark shadows from the mountains and in the craters. Although the Apollo landing sites are observable during the waning Moon, but disappear in reverse order of their appearance during the wax­ing phase. The waning phases appear between midnight, gradually towards dawn, when most of us are asleep. Those readers with insomnia are invited to enjoy the still and quiet of these early a. m. hours and enjoy lunar observing.

Funding for scientific space exploration often is met with resistance by politicians and the general public. In a parallel example, the development and building of the International Station has been shared among several spacefaring nations with great success. A mission to Mars offers the opportunity for the development of new industries and new jobs to the benefit of all.

There is an enormous cost associated with space exploration. Traditionally, government-funded agencies such as NASA and the European Space Agency (ESA) have used monies obtained through tax dollars to pay for the expense of space. In many cases, such as the Department of Defense Global Positioning System, commonly known as GPS or SatNav, there are benefits that can be derived by the everyday man. Weather services are reliant on meteorological photo tracking of weather fronts and storms. The Apollo Program was funded using public funds, with the impetus of the Cold War driving the effort.

New funding sources may be needed to finance the herculean effort of a mission to Mars. Cost estimates for a Mars effort range from a paltry $6 billion to an enor­mous estimate of $500 billion.

An innovative and precedent making approach may need to be explored. In 2009, a science fiction television show called Defying Gravity offered a commercial solution to raising funds. In an episode called “Fear”, an in-space promotional event using the astronauts was scheduled, with the proceeds funding experiments conducted during the mission. Selling advertising space, naming rights, and com­mercials is an unexplored avenue for paying the expenses of space exploration, such as a Mars mission. Just imagine if this had been done during the Apollo era. The Saturn V could have been launched displaying the name brand of a leading soda, with the astronauts eating and endorsing freeze dried foods on camera during broadcasts to American television networks. General Motors, the developer of the lunar rover, could have taken better advantage of their participation in the Apollo program. One wonders if funding had been obtained in this fashion, would Apollo 18 have been a lunar landing instead of an orbiting handshake?

Many of the readers of this book already own a telescope, on a stable mount, with a case or two of eyepieces and accessories. These readers are suitably equipped to observe the Moon and search for Apollo.

To the readers without a telescope, get one. Astronomy is a wonderful hobby, filled with potential personal discoveries. For the price of a pair of bifocal high index eyeglasses, a nice 80 mm refractor on an alt-azimuth mount with two Plossl eyepieces can be obtained. This setup serves as a great care free introduction to the hobby, and when aperture fever takes hold (it always does) and a larger telescope is procured, the 80 mm refractor still has a role as a grab-and-go scope. The 80 mm refractor’s sharp images are always appreciated.

NASA developed the Surveyor Program as the follow-up to the Ranger program. Ranger proved that NASA could hard crash a spacecraft into the Moon. Surveyor was NASA’s opportunity to achieve soft landings on the Moon. Additionally, NASA set scientific goals of Surveyor to gather data about the Moon’s surface, through photographs and digging scoops.

In those early days of the NASA lunar program, very little was known about the Moon’s surface. There were scientists that feared that the Moon’s surface was coated in a thick lunar dust that a lunar lander would be swallowed up and sink into the Moon’s surface. Therefore, Surveyor’s mission included experiments to test the nature of the lunar surface, including a mechanical scoop to test the firmness and granularity of the lunar soil.

As with Ranger, not all of the Surveyor missions were successful. Surveyor 2, originally targeted for Sinus Medii, or Central Bay, suffered a failure in one of its vernier rocket motors, resulting in a tumbling flight to the Moon and its crashing near the Copernicus Crater.

Surveyor 4 also crashed in its mission to Sinus Medii ( a Sinus Medii jinx?!?!). After a faultless flight to the moon, telemetry signals from the spacecraft ceased during the landing phase, about 2.5 minutes before touchdown. Contact with the spacecraft was never reestablished, and the mission failed. The engineers’ specu­lated that the solid fuel retro rocket exploded during the end of its scheduled burn.

In all, seven unmanned Surveyor lunar missions were launched between May 1966 and January 1968. Surveyor 1, 3, 5, 6, and 7 successfully accomplished a soft landing on the lunar surface. In addition to demonstrating the feasibility of lunar surface landings (and not disappearing into the moon dust!), the Surveyor missions obtained lunar photos, and gathered both scientific and technological information needed for the manned Apollo program. Four spacecraft, Surveyor 1, 3, 5, and 6, returned data from selected mare sites to support the Apollo program. Surveyor 7 provided data from a highland region.

Fig. 11.2 Finder chart. Courtesy of the author

Here again, as with sighting the Ranger impact sites, locating and viewing the Surveyor landing sites serves as extra credit to the backyard observer.

Fig. 11.3 LRO View of Surveyor 1. Photo courtesy of NASA and Arizona State University

Site Selection

All Surveyor landing sites, except for the last one, were selected primarily because they were being considered as Apollo landing sites. The landing site selected for Surveyor 1 was in the southwest part of Ocean of Storms. The spacecraft came to rest within about 15 km of the target point, on a flat surface inside a 100-km crater, one radius from the edge of a rimless 200-m crater.

Surveyor 1 was the first U. S. spacecraft to land softly on the Moon, proving a variety of new equipment and spacecraft design, and validating the technique for landing on the Moon. It returned a large quantity of scientific data during its first two days of operation on the lunar surface. Following its landing, the spacecraft transmitted 11,240 high-resolution television pictures back to NASA. Surveyor 1 completed its primary mission on July 14, 1966, after transmitting television pictures, data on the bearing strength of the regolith, temperatures, and radar reflectivity of the Moon. Subsequent engineering interrogations of the spacecraft were conducted through January 1967.

The site selected for Surveyor 3 was in the southeast part of Ocean of Storms. The spacecraft came to rest in a subdued, rounded crater about 200 yards in diameter approximately 230 miles south of the Copernicus Crater. This site became a future landing site of an Apollo mission. As seen in Chapter 4, Apollo 12 landed within walking distance and astronauts Pete Conrad and Alan Bean visited Surveyor 3 and returned with component parts of the spacecraft for examination and study by NASA engineers.

The data from Surveyor 3 showed that it touched down on the lunar surface three times before the landing was completed. Surveyor 3’s engines did not shut down as intended. The spacecraft moved approximately 65 feet between the first and second touchdowns and about 36 feet between the second and third. The engines finally shut down prior to the third touchdown. A final translation movement of about 1 feet occurred following the third touchdown.

Like its predecessors, this mission carried a survey television camera, as well as other instrumentation for determining various properties of the lunar surface mate­rial. Additionally, it carried a surface sampler instrument for digging trenches, making bearing tests, and otherwise manipulating the lunar material in view of the television system. During its operation, which ended May 4, 1967, Surveyor 3 acquired a large volume of new data and took 6326 pictures. The surface sampler, during its 18 hours of operation, accumulated samples which yielded significant new information on the strength, texture, and structure of the lunar material to a depth of about a half a foot.

The site selected for Surveyor 5 was in the southwest part of the Sea of Tranquillity. Surveyor 5 landed in a dimple-shaped, two car garage-sized rimless crater, the larg­est of a small chain of rimless craters. A backyard observer when sighting the Apollo 11 landing site will also have the Surveyor 5 site within the field of view.

This spacecraft was basically similar to its predecessor, except that the surface sampler was replaced by an alpha-backscatter instrument. In addition, a small bar magnet was attached to one of the footpads. Because of a critical helium regulator leak, a radically new descent profile had to be designed for the spacecraft. Surveyor 5 performed flawlessly and landed softly. Once safely on the Moon, the spacecraft functioned well and outperformed the previous missions. During its first lunar day

of operation on the Moon, 18,006 television images of exceptional quality and high scientific content were returned to Earth. On October 15, 1967, after having spent 2 weeks in the deep freeze of a lunar night, Surveyor 5 responded immediately to the first turn-on command and resumed operation, returning 1048 additional pic­tures and 22 hours of additional data.

The Surveyor 6 Mission

Fig. 11.7 Panoramic Lunar mosaic from Surveyor 6. Courtesy of NASA

Fig. 11.8 Panoramic Lunar mosaic 2 from Surveyor 6. Courtesy of NASA

Site Selection

The landing site chosen for this mission was in Sinus Medii, site of two previous Surveyor failures. The Sinus Medii curse was finally broken, with Surveyor 6 land­ing in the center of the Moon’s Earth-facing hemisphere. Surveyor 6 marked the last of four potential Apollo landing areas designated by the Surveyor program planners. The spacecraft landed on a nearly flat, heavily cratered mare area, about 200 yards northwest of the base of a ridge about 100 feet high.

The performance of Surveyor 6 on the lunar surface was virtually flawless. From touchdown until a few hours after sunset on November 24, 1967, the spacecraft transmitted 29,952 television pictures and the alpha-scattering instrument acquired 30 hours of data on the chemical composition of the lunar material.

As part of the surface mechanical properties investigation, Surveyor 6 performed a “hop” maneuver, moving 2.5 m away from its original landing area. This maneu­ver provided excellent views of the surface disturbances produced by the initial landing and the effects of firing rocket engines close to the lunar surface. Photography obtained after the hop contributed to the soil mechanics investigation.

On November 26, 1967, the spacecraft was placed in hibernation for the two – week lunar night. Contact with the spacecraft was resumed for a short period on December 14, 1967.

The Surveyor 7 Mission

Fig. 11.9 Panoramic Lunar mosaic from Surveyor 7. Courtesy of NASA

Site Selection

Surveyor 7 was the only unmanned pre-Apollo landing mission sent to an area for mainly scientific reasons. All of the previous Surveyor missions were targeted for safe mare regions. The Surveyor 7 site selection was for a highland region with a rugged, rock-strewn ejecta blanket near Tycho Crater. The spacecraft landed less than 1.5 miles from the center of the target circle, about 18 miles north of the rim of Tycho. The backyard astronomer needs merely to sight the Tycho Crater and view the north rim to view the Surveyor 7 landing site.

Despite the more hazardous terrain in the landing area, Surveyor 7 landed without incident. 20,993 television pictures were obtained during the first lunar day.

An additional 45 pictures were obtained during the second lunar day. The alpha­scattering instrument failed to fully deploy on its own, so the surface sampler was used to place the instrument on the surface, and enabling the device to function. The surface sampler moved the alpha-scattering instrument to two other locations for more data gathering. In addition to acquiring a wide variety of lunar surface data, Surveyor 7 also obtained pictures of Earth and performed star surveys. Laser beams from Earth were successfully detected by the television camera in a special test of laser-pointing techniques, as a proof-of-concept prelude to the Apollo LRRR experiment.

Post-sunset operations were conducted for 15 hours after local sunset at the end of the first lunar day. During these operations, additional Earth and star pictures were obtained, as were observations of the solar corona. Operation of the spacecraft was terminated 80 hours after sunset. The spacecraft was reactivated for the second lunar day on February 12, 1968, and operated until February 21, 1968.

It is important to be familiar with the type of major features of the Moon prior to search­ing for the Apollo landing sites. In 1651, a Jesuit astronomer named Giovanni Battista Riccioli created and published a system of nomenclature still in use today. Originally written in Latin, many of the lunar names have been Anglicized. For the comfort of the readers, Seas, Ocean, Bay, and other English nomenclature will henceforth be used in this book, except in one case. Mare Cognitum will be used in its Latin form, because it translates to “the sea that has become known”, which is extraordinarily awkward.

• Mare or Sea – The near side of the Moon is characterized by large, dark, seem­ingly smooth areas that early astronomer Riccioli called Mare, or Sea (with the plural Marias or Seas). From the Apollo missions, scientists now know that what looked like water to early astronomers is comprised of vast fields of basalt lava flows. In keeping with the water-based nomenclature for the Moon, Riccioli named one oceanus (ocean), and several dark areas as lacus (lake), palus (marsh) and sinus (bay). The ocean, lake, marsh and bay have the same nature and characteristics, but differ in size.

• Major craters – The Moon is obviously pockmarked with craters, the majority being impact craters left from meteors over the eons. Two of the larger craters are named for the pioneering astronomers Tycho Brache and Copernicus. The meteor impacts that created these landmark craters spread lunar debris across the near face of the Moon, and influenced NASA planners in their selection of Apollo landing sites, as will be seen in the Apollo mission chapters of this book.

• Highlands and Mountain Ranges – The highlands and mountain ranges of the Moon provide the brightest images of the Moon. Some mountain ranges, such as the Apennines and the Alps are actually parts of the crater rim surrounding the Sea of Rains. Other peaks are part of mountain ranges that project above the surface as part of fluid dynamics resulting from the liquefaction of surface rock following a meteor impact. Apollo landing sites in the highlands gathered scien­tific data, rock and soil samples from these regions to provide a comparison with the basin material, as detailed in the Apollo mission chapters of this book.